DESCRIPTION: Percutaneous transluminal coronary angioplasty (PTCA) has become the predominant treatment for symptomatic coronary atherosclerotic lesions. Despite its prevalent use, this technique continues to be plagued by a restenosis rate of 30-40% with resultant enormous added health care costs and patient morbidity. Radiation therapy applied locally at the site of coronary balloon injury shows great promise to reduce this restenosis rate. All current and proposed techniques of radiation delivery carry significant drawbacks of safety and effectiveness of uniform dose application. This project proposes a unique, novel approach to radiation delivery through utilization of a short-lived positron emitting isotope, Cu-62, produced by a generator system. This isotope will be delivered into the angioplasty balloon inflation time. Safety issues are addressed through use of a Cu-62 chemical system assuring blood binding in the event of balloon rupture combined with the short 9.7 minute half life of Cu.62. Use of a balloon delivery system offers significant advantages over solid band and wire sources which dominate in this field. These solid systems are very difficult to position in a manner assuring uniform circumferential radiation dose to the artery wall. Also there are substantial safety issues relating to dislodgment in the patient. Use of Cu-62 in a balloon delivery system can provide both complete safety and optimal uniformity of dose delivery. PROPOSED COMMERCIAL APPLICATION: Restenosis of arteries following coronary angioplasty occurs in roughly 150,000 patients each year. The technology developed in this application could provide a safe, effective, and low-cost method to substantially reduce the incidence of this restenosis. By preventing the need for additional interventional procedures, such as bypass surgery or further PTCA, it could significantly reduce overall health care costs and thus would likely find a sizable market. In addition, the proposed method of radiation therapy could potentially be used to treat other sites of harmful cellular proliferation.